The present invention relates to a vehicle cornering headlamp system in which the direction of illumination of a headlamp is varied in association with a steering wheel turning operation.
A vehicle, especially an automobile, has headlamps for producing a light beam forward of the vehicle at night. The direction of illumination of the headlamps is fixed so that the main beam of light is applied directly forward of the vehicle. However, when the vehicle is traveling along a curve, the headlamps cannot sufficiently illuminate objects ahead of the vehicle. In other words, during travel along curves and in cornering, hazardously objects located in the path of the vehicle may not sufficiently be illuminated by the headlamps.
In order to overcome this difficulty, recently a vehicle cornering headlamp system has been proposed in which the direction of illumination of the headlamps is changed in association with steering wheel turning operations so that objects located in the actual path of the vehicle are sufficiently illuminated.
However, in the conventional vehicle cornering headlamp system, the variation of direction of illumination varied linearly with respect to the steering angle, that is, the change is the same in the case where the steering wheel is turned away from the straight-ahead steering position as in the case where the steering wheel is returned to the straight-ahead steering position, as shown by the graph in FIG. 11. As a result, the direction of illumination returns to the straight-ahead direction of the vehicle at the same time the steering wheel is returned to the straight-ahead steering position.
In the case where the vehicle travels around a curve, in general, the operator decelerates the vehicle before it reaches the curve, and, after the vehicle reaches the curve, accelerates the vehicle, then returns the steering wheel to the straightahead position before the vehicle reaches the end of the curve. When returning the steering wheel, studies have found that the driver's eyes are no longer on the curved part of the road, but on a linear extension of the curve. Due to the factors, the direction of illumination of the headlamp is not coincident with the direction of the driver's eyes immediately before the vehicle reaches the end of the curve; that is, the driver may feel the change of the direction of illumination of the headlamp inharmonious with the steering-wheel turning operation.